Hi,

Am Mon, 2 Mar 2015 04:19:23 -0800 (PST) schrieb San:

Aug 31 2014 : $74.58
Oct 01 2014 : $75.46
Oct 15 2014 : $74.29
NOv 01 2014 : $71.68
Dec 01 2014 : $70.73
Dec 16 2014 : $68.65
Jan 12 2015 : $68.66
Jan 17 2015 : $66.64
Feb 04 2015 : $64.60

try:

=AVERAGEIFS(B:B,A:A,"=" &DATE( 2014,9,16),A:A,"<="&DATE(2015,2,15))


Regards
Claus B.
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Vista Ultimate / Windows7
Office 2007 Ultimate / 2010 Professional